ISA changes

Qualcomm vs SiFive - Potential split in the ISA?

Recently Ian Cutress reported on layoffs at SiFive, however the more interesting story may be tension between Qualcomm and SiFive around the direction of RiscV. Discussion in this thread on HN amoungst industry insiders indicated that Qualcomm is keen to deprecate variable length instructions and the C extention in order to simplify the implementation of high performance RiscV cores. According to comments (I can find no link) SiFive has a strong preference for preserving the C extentions, presuably for code compression and performance reasons.